CHART I. 1,000 LITTORINA LITTOREA. TEN nv, WALES. 



4- 





i S- 1 9 mm. 



16-17 mm. 



-15 mm. 



So Si 82 83 ^4 85 S6 87 83 89 90 91 92 93 94 95 96 97 98 99 100101102 103104105106 



